LINCOLN MARK VII AIR FILTER PROBLEM

1987 Lincoln Mark VII • V8 2WD Automatic • 115,000 miles

Hi.I have a 1987 Lincoln Mark VII. The car is getting poor gas mileage, about 7.5 miles/gal.I usually get around 12 city.I have recently changed the fuel and air filters. Seemed to help. Next day back to the same. Its got new plugs and wires last year. Maybe mass air flow sensor or injectors?Can you help?Regards, Piero